Farriery is the craft of shoeing horses. Prior to actually attaching a horse shoe to a horse's hoof, however, the hoof must be appropriately shaped to accept the shoe so as to allow the horse to maintain an appropriate gait. Shaping the horse's hoof prior to shoeing typically involves use of a number of tools, including a farrier nippers. Farrier nippers are used to trim the area of the hoof where the shoe is to be mounted. This is necessary because, somewhat like a human fingernail, this area grows over time.
Farrier nippers are formed from two elongated members, each member having a relatively long handle at a proximal end, a jaw at a distal end, and a flattened pivot region between the handle and the jaw. The two elongated members are attached by a pivot, which is typically a rivet, passing through the pivot regions of the two members so that the two members can pivot with respect to one another in a plane of motion of the nippers. The jaws of the elongated member are generally "C"-shaped and configured so that the interior concave surfaces of the "C"s oppose each other to form an interior edge of the jaws. Opposing blades are formed at die distal ends (the upper endpoint of the "C"s) of the jaws. The edges of the blades extend transversely in a direction which is perpendicular to the plane of motion of the nippers and must be relatively sharp and preferably relatively hard so that they retain their sharpness. A curved ("C"-shaped) neck attaches each blade to a base of its respective jaw adjacent to its respective pivot region. The interior concave surface of this neck is typically either flat or slightly rounded in prior art nippers.
Typically, the elongated members are formed by forging. Further, it is known to forge the blades and handles unitarily, that is as one piece, as a continuation of the elongated members. To be able to forge the relatively thin blades to their full transverse extent, relatively high forge pressures are required. As such, a forge hammer is often used in place of a forge press. The forge hammer is a relatively large machine that can produce forging pressures greater than that of a typical forge press. However, generally, a forge hammer is considerably more expensive than a typical forge press. Accordingly, to manufacture farrier nippers having blades formed unitarily with the elongated members can be relatively expensive.
Once the elongated members are formed, it is desirable to heat treat the edges of the blades to increase their hardness so that they will retain a relatively sharp edge, typically using "induction hardening." During the induction hardening process, the blade edge is heated using a conventional electrical induction coil to a relatively high temperature and then rapidly cooled.
It is also known to fabricate farrier nippers wherein blade members are formed separately from the elongated members. The blade members of nippers fabricated in this way are typically machined from a solid block of steel resulting in a substantially flat blade portion adjacent to a blade edge with a slot generally perpendicular to a plane of the flat blade portion located in a mounting portion of the blade member adjacent to the blade portion. The necks of the jaws of the elongated members of the nippers each have a tongue which is sized to closely mate with the slot of the mounting portion of the blade insert. Apertures extending perpendicularly to the plane of motion of the nippers are formed in the tongues to line up with transverse apertures in the mounting portions of each blade insert. Drive pins can be press fitted in the aligned apertures to attach the blade inserts to their respective elongated members.
Forming farrier nippers in this way allows the elongated members of the nippers to be fabricated using a forge press rather than a forge hammer because relatively high forge pressures are not necessary to form the thin, transversely extending blades. As such, overhead in manufacturing the nippers can be reduced. However, forming a blade insert, with its thin blade, apertures and slot from a block of metal can produce a relatively high amount of waste material. This can increase the manufacturing costs of the nippers.
As with most cutting tools, the blades of a farrier nippers are preferably hardened so that they will hold their edge. Typically, the blades are hardened using an induction hardening process. Induction hardening involves heating the blade above a critical temperature (preferably above 1500.degree. F. for common steels) and then rapidly cooling it. The rapid cooling from above the critical temperature is responsible for the hardening of the blade and is usually referred to as "quenching." In production of farrier nippers, induction hardening is typically carried out as a separate manufacturing step. As such, it can add to the cost of manufacturing.
Farrier nippers are used by opening the jaws by spreading the handles, placing the blades on either side of a portion of the hoof wall of a horse's hoof to be removed, and closing the jaws to trim that portion. On occasion, the section of a hoof wall to be removed is bulkier (thicker) than the area where the cut will take place to remove bulky section. When this occurs, the bulky section can bind on a flat or rounded inside surface of the neck of the jaws and not allow the nippers to close entirely to make the necessary cut. Additionally, some farrier nippers have a "stop" where the base of the two "C's" of the jaws meet to prevent the blades from crossing over one another during a cut. A piece of hoof or other foreign material may get caught in the stop between the base of the two "C's" and prevent the jaws from closing entirely,, thereby preventing completion of the cut.
Accordingly, there is need for both improved design in farrier nippers and improved methods of manufacturing of farrier nippers. The present invention overcomes deficiencies in the prior art by providing increased cutting functionality. It further overcomes deficiencies in the prior art by not requiring the use of a forge hammer (as was required for unitary nippers), while avoiding the cost and complexity of the pinned-blade construction. Additionally, the present invention allows the elimination of a separate induction hardening step in manufacturing a farrier's nippers.